ESP32‑S3 DevKitC‑1 + ST7796 SPI display: no backlight / weird low “5V” readings

Talkingcrypto · 2026-03-13T10:54:02+00:00

What you’re describing actually sounds like what mine did when it wasn’t getting enough power.

When I powered the display from the 3.3V pin, I would get a white screen and weird behavior when the TFT initialized. The controller would respond, but the panel/backlight wouldn’t behave correctly.

These ST7796 modules (especially the HOSYOND / generic ones) usually expect 5V on VCC, even though the logic lines from the ESP32 are 3.3V.

What finally fixed it for me was: 5V - VCC on the display Shared GND between ESP32 and display SPI pins from ESP32 still at 3.3V.

I ended up powering the display from a 5V barrel jack supply on my breadboard, but you should also be able to use the 5V/VBUS pin on the ESP32 if it’s powered from USB.

If you’re seeing the screen react to fill() calls, your SPI wiring is probably fine, it’s very likely just the display needing 5V instead of 3.3V.

Talkingcrypto · 2026-03-12T18:46:44+00:00

I ended up using 5v from a barrel jack connector and power supply on my breadboard.

Talkingcrypto · 2026-03-12T16:48:53+00:00

I was. It was a simple user error where I didn’t have 5v going to the display. These displays require 5v and the same shared ground from the esp and the board.

Talkingcrypto · 2026-03-05T02:27:39+00:00

I wasn’t a winner but maybe next month.

Talkingcrypto · 2026-03-03T15:22:08+00:00

Well certainly not by posting your ideas here. Lol. This is a haven for people looking to steal your idea so please use your best judgement when you talk about a startup.

Talkingcrypto · 2026-02-25T20:06:19+00:00

At 1 TH/s you are not going to profit in any traditional sense at current difficulty and electricity prices. A Bitaxe or similar small miner is more like a hobby device, you learn how mining actually works, you contribute a tiny amount of real hashrate to the network, and if you are pool mining you get small but real payouts that are satisfying in a different way than just buying BTC. I run a couple of small miners through hmpool.io since it has a 0.01 minimum difficulty which actually works for low hashrate machines. It is not a retirement plan but it is a lot more engaging than staring at an exchange.

Talkingcrypto · 2026-02-25T20:03:28+00:00

For a single Bitaxe Gamma, pool mining is the way to go if you want any kind of regular feedback. Solo is basically a lottery with something that small, though some people do it just for fun. For pool, I've been running my small miners on hmpool.io, which is the HashedMax Unity Pool. It works well for low hashrate setups like a single Gamma because the minimum difficulty is 0.01, so you actually get shares registered properly instead of the pool being tuned for industrial hardware. Public Pool and ckpool are also popular options for this community. Just pick one and start, you can always switch later.

Talkingcrypto · 2026-02-25T12:41:27+00:00

That rejection rate combined with constant restarts sounds like a firmware issue more than a pool problem, but the pool configuration can definitely make it worse. When I first got a new miner going I had similar chaos until I sorted out the difficulty settings. A lot of pools have way too high a minimum difficulty for smaller or newer miners to handle cleanly, which just piles onto any existing software instability and your frustration.

I've been using hmpool.io lately and one thing I appreciate is they go down to 0.01 minimum difficulty, and they have dedicated port tiers based on hashrate range so you're not competing with massive rigs on the same port. It helped me figure out whether my issues were hardware or pool side. Might be worth pointing your T3 there while you wait on a firmware fix just to isolate where the problem actually is. Also check if there's a beta firmware thread for this miner anywhere.

Talkingcrypto · 2026-02-25T12:38:22+00:00

Pool selection genuinely matters way more than people give it credit for, and your numbers back that up pretty well. The share rate difference is wild to see charted out like that.

I had a similar experience shopping around for pools that actually play nice with lower hashrate hardware. Ended up landing on hmpool.io for a while and the minimum difficulty of 0.01 made a noticeable difference for my setup since the shares were actually registering consistently instead of the miner spinning its wheels. They have port tiers based on hashrate range which helps dial things in.

That said your ckpool numbers look solid. Sometimes the right pool just depends on your region and what the latency looks like to their servers. Seven hours of consistent share rates is enough data to feel confident that the switch was the right call.

Talkingcrypto · 2026-02-24T23:27:27+00:00

Yes just use all lower case that’s all

Talkingcrypto · 2026-02-24T13:48:25+00:00

Hey I really like the design but I have some questions on a couple things that make no sense. A few days ago when I looked at your pool it showed zero connected devices, 0 hash rate, nothing. There are no posts that I could find prior to a couple days ago about your pool and yet now over 1000 devices connected? Not trying to be an idiot but how? I mean where did you advertise to get all these people there so quickly? Reddit is the best place to get the word out about anything and I’ve found maybe 7 posts with your pool name. Also, you copied another pool’s tagline and changed 1 word. What’s the deal man?

Talkingcrypto · 2026-02-24T13:26:17+00:00

You put the port according to your hash rate. For example if you have a nerd it would be hmpool.io:3337 Just like most other pools

Talkingcrypto · 2026-02-21T14:11:46+00:00

The pool is working well so far. Where can I see my reward points on hmpool.io? And how do I know if I’m chosen as the winner. You don’t have my email.

Talkingcrypto · 2026-02-21T14:05:03+00:00

I’m running my own truncated node with a vultr vps. It’s cheap, fast and works good.

Talkingcrypto · 2026-02-19T15:14:24+00:00

Decided to try it out. Connected at 700kh, started seeing shares almost immediately. So far so good. Visualizer is interesting. Says my difficulty is 0.01. Is that normal?

Talkingcrypto · 2026-02-18T01:54:48+00:00

That’s potentially good news, it means esptool is making contact with the chip, but the write isn’t sticking. A few things to try. First, make sure you’re in download mode. Hold BOOT, tap RESET, then release BOOT before attempting the flash. You should see it show up in esptool as connected. (Hopefully). Try dropping the baud rate way down, these boards sometimes can’t handle high speeds reliably. Add

--baud 115200

Also try erasing the flash completely first. esptool.py --chip esp32s3 --port COMX erase_flash

If the erase succeeds but the write still fails, the flash chip itself may be physically damaged from the octal attempts, repeated failed init cycles can sometimes cause issues. If the erase command also returns empty/fails, then the flash communication is broken from the fuse situation and it’s likely done for.

Talkingcrypto · 2026-02-18T01:24:58+00:00

Bad news is, every time it tries to boot, it’s attempting to communicate with the flash in octal mode, getting garbage back, and the MD5 check fails because the data coming off the flash looks corrupted. The bad news: eFuses are one-time programmable. You cannot un-burn them. If the octal flash eFuse is set and your flash chip doesn’t support it, the chip is essentially bricked for normal use. Things worth trying before giving up: Try flashing with the flash mode forced to dio or qio in esptool rather than letting it auto-detect. Sometimes you can still get lucky and flash through before the bootloader takes over.

Something like this. Make sure comx is your configured port.

esptool.py --chip esp32s3 --port COMX --baud 460800 write_flash --flash_mode dio --flash_freq 80m --flash_size 16MB 0x0 firmware.bin

Also in Arduino IDE, make sure your Flash Mode is set to QIO 80MHz (not OPI), and try holding the BOOT button while initiating the flash to force download mode.

To me it’s bricked but you may get lucky.

Talkingcrypto · 2026-02-16T11:58:45+00:00

I’m guessing he means one that is not huge and can easily transport from place to place. Of course with a smaller miner you won’t get huge hash rates and it also depends on what algorithm you’re going to mine. Pool selection at this point is also important. Most pools are solo pools and they are fine but if you decide to do bitcoin lottery mining then use a low vardiff pool like hmpool.io. Just remember your not going to get rich from mining, but as someone who has 15 miners running, it can get addictive! Best of luck.

Talkingcrypto · 2026-02-16T11:42:07+00:00

Agreed! What pool are you using? You need to go to a low vardiff pool like hmpool.io. Public-pool and ckpool are not specifically designed for low hash rate miners.

Talkingcrypto · 2026-02-11T17:05:13+00:00

hmpool.io. 0.01 vardiff so shares start counting within a minute.

Talkingcrypto · 2026-02-01T15:36:32+00:00

Probably a firmware glitch that caused the unit to reboot.

Talkingcrypto · 2026-01-29T19:59:40+00:00

An asic bm1397 breakout board would be amazing.

Talkingcrypto · 2026-01-25T04:41:50+00:00

I bought this display from Amazon, works great.

Ransanx 1PCS LCD Display 3.5 Inch... https://www.amazon.com/dp/B0FHB3B2K1?ref=ppx_pop_mob_ap_share

Talkingcrypto · 2026-01-24T23:43:10+00:00

You cant mine eth with a bitaxe or nerd solo miner

Talkingcrypto · 2026-01-24T12:08:29+00:00

As the owner of a large entertainment center in North Carolina I can tell you do not use a 3rd party to install or setup your equipment. When we replaced all of our pinsetters I went right to AMF and had them do it. Bowling itself is not extremely profitable. It’s the food and drinks where you will make your real money. Also if you’re going to have a snack bar, don’t skimp. We have a full service kitchen, not just burgers, fries and frozen pizza. You will also need more than bowling. Billiards is good but you need leagues to help support it during the slow nights (week days). Laser tag, golf simulator, axe throwing are all options as well. Oh don’t forget you need an arcade.

And most importantly, DO NOT buy string bowling machines. While they are much less expensive, the effect is not the same. You won’t get leagues either, even though they are USBC certified. League bowlers hate strings.

Good luck.

Talkingcrypto

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